Abrasive tool



Oct. 20, 1936. A. A. HODGKINS 2,058,229

A'BRASIVE TOOL Filed Jan. 20, 1953 I Sheets-Sheet INVENTORJ ALBERT A.HODGlf/MS ATT RNEY- Oct. 20, 1936.

- Filed Jan. 20, 1933 A. A. HODGKINS ABRASIVE TOOL 2 Sheets-Sheet 2 FI610. e0

INVENTOR- 2,

Patented Oct. 20, 1936 UNITED STATES j PATENT OFFICE,

ABRASIVE TOOL Albert A. Hodgkins, Leonia, N. J., assignor to SurfacingWheel Corporation,- New York, N. Y.,

a corporation of Delaware Application January 20, 1933, Serial No.652,622

1 Claim. (CL 29-78) This invention relates to power driven abrading,cutting and polishing tools.

In many situations, articles of manufacture must be treated to removeexcess material, en-

built by pouring concrete between forms made of rough boards, showridges where the boards of the forms joined one another and the wholeconcrete surface appears rough and unfinished due to the texture of therough board. In the renovation of articles of manufacture, it is oftennecessary to remove a coating of paint, or other preservative. And metalarticles, such as castings, forgings, metal sheets and plates and thelike often have a scale of iron oxide which must be removed prior to useor finishing. Ship bottoms must also be cleaned periodically to removebarnacles.

Heretofore, coatings, encrustations and other surfaces, even on shipbottoms, have been removed by means of wire bristle brushes, grindingwheels of composition or other material, steel burring wheels and thelike. Such abrasive means have had a relatively short life. In the caseof wire bristle brushes, the bristles spread apart and break afterrelatively few hours. Grinding wheels, when used on relatively softmaterial such as wood, copper, aluminum or plastic materials, soonbecome clogged with the material abraded and have to be resurfaced, thatis,

the clogged surface is removed by redressing the surface of the wheel.In a short time, so much of;. the wheel has been removed as to render itin It is also fre-.

capable of further practical use. quently necessary, with existingabrasive devices, to use one tool, such as an emery wheel to cut off theundesired surface and a second tool, such as a wire bristle brush topolish such surface.

For instance, on concrete, to remove the rough spots formed by thewooden forms, and smooth the surface, abrasive wheels, chipping discsand wire brushes are used in conjunction with one another, thusincreasing the time required to complete the smoothing operation, aswell as the expense thereof.

Certain grades of steel, as they come from the mill, have a hard skin ortough surface which, in ordinary machine handling, requires time toremove and, in its removal, is hard on the present tool steel. I It isnow removed in a planer or lshaper or by grinding-wheels or millingmachines,

but the removing operation is necessarily slow as the tools overheat andmust be run at slow speeds and require constant feeding of acuttingrfluid to the cutting tool. 7

One object of the present invention -is to pro 5 vide a surface orcoating removing devicewhich shallbe more effective than existingdevices and which shall have a longer life.

Another object of the invention is to provide a device of the characterdescribed which shall both. 10

cut or abrade undesired material and polish the surface in one and thesameoperation- It is also an object of the invention to provide such adevice with cutting and polishing teeth of aresilient character whichshall retain their. 15

shape and characteristics substantiallyindefinite- 1y, only the cuttingedge wearing down to the limit of its effectiveness.

The invention also seeks the provision of teeth for devices of thecharacter described which shallnot crystallize and break in use.

Afurther object of the invention is a tool of the character describedhaving, a plurality of flexible or resilient teeth therebyincreasing'the cutting ability of the teeth and giving the teeth aself-cleaning ability.

Still another object of the invention is a device of the characterdescribed which ,will avoid overheating. Accordingly, teeth are providedwhich are spaced from one another on a hub whereby heat is dissipatedreadily.

Yet another object of the invention is a de- .vice of the characterdescribed which will not clog with the material abraded.

The invention seeks further a device of the character .described inwhich the cutting or polishing teeth are replaceable whereby differentdegrees of abrasive or polishing. action is obtained and worn teeth maybe1replaced as required. I I 1 Furthermore, an abrading tool is soughtby this invention, which may be operated at relatively high speeds andno cutting. fluid or cooling medium is required.

I The invention has for another of its objects a device of the characterdescribed in which the abrading or polishing elements may not becomedisplaced with respect to one another to leave portions of-the surfacenot acted-upon.

The invention further seeks a cutting and/or. polishing device which ispractical from the standpoint ofease and cheapness' of manufacture andconvenience;universality. and durability in use.

These and other objects of the 'inventionand the means for theirattainment willbe more apiparent from the following detaileddescription, taken in connection with the accompanying drawingsillustrating various embodiments by which the invention may be realizedand in which:

Figure 1 is a view, in side elevation, showing one form taken by thedevice of this invention;

Figure 2 is a view, in end elevation, looking from the left in Figure 1and showing one way in which the cutting teeth of this invention may besecured in a hub, parts being broken away in the interest of clearness.

Figure 3 is an enlarged fragmentary sectional view showing the teeth inthe hub, taken on the line 3-3 of Figure 2;

Figure 4 is a detail view showing teeth used in cutting or abrading asurface;

Figure 5 is a detail view similar to Figure 4 showing the teeth used inpolishing a surface;

Figure 6 is an exploded view showing the blades going to make up oneform of the cutting or polishing tooth of this invention;

Figure '7 is a view showing a modified form of the invention;

Figure 8 is a sectional view taken on the plane indicated by the line 88of Figure '7 and looking in the direction of the arrows;

Figure 9 is a sectional view, taken on a diameter of still anothermodification of the abrasive wheel of this invention;

Figure 10 is a fragmentary view, on an enlarged scale showing details ofconstruction of the modification of Figure 9; and

Figure 11 is a fragmentary view showing the modification of Figure 9 inside elevation, parts being broken away in the interest of clearness.

In carrying the invention into effect, a plurality of teeth aredistributed in spaced relation about the periphery of a hub or wheel.

The cutting or abrading tooth of this invention is laminated. Were asingle blade, such as the leaf or lamination l2 of Figure 4, 5 or 6,used and tightly clamped in a holder and moved across a surface at highspeed with cutting or abrading friction, it would be deflectedsubstantially in a plane and bend on a transverse line at the point ll(Figure 4 or 5) at which it is secured in the holder. The repetition ofshocks, as the holder is revolved, of the blade contacting with the worksoon crystallizes the steel of the blade at the line II and causes it tofracture. If, however, the blade I2 is yieldingly reenforced so that itbends in an arc as shown in Figures 4 and 5, no deleterious eifectsarenoted and the blade will function until it is worn down after longuse to a length less than its designed effective operative length.

As shown in Figures 4 and 5, the cutting or abrading tooth, as a whole,is indicated at II]. It is conveniently comprised of a plurality offormed blades or leaves or laminations of different lengths. The blade[2 is the longest. Back of this blade l2 (considering the direction ofrotation as shown by the arrow in thesefigures) is a shorter blade I3and back of the blade I3 is a still shorter blade l4. Any number ofblades as deemed necessary may be used. The respective blades l2, l3 and[4 are shorter for stiifness, as in Figure 4, where abrading is requiredand longer for greater flexibility as shown in Figure 5 where polishingor use on soft materials is required. The blades are held in a slot ISin a holder l8. In commercial use, a series of such multiple orlaminated teeth [0 are disposed about the periphery of a cylindricalholder, as seen in Figures 1 and 2, all disposed in the same plane,

equally spaced about the circumference. Then,

as the holder revolves, the teeth come into contact with the surface tobe acted upon, in succession, each tooth removing a portion of thesurface.

The hub may comprise one or a plurality of discs or holders 20 eachformed with a plurality of the radial slots l6, preferably equallyspaced about the periphery. The thickness of each disc 20 is less thanthe width of the teeth In so that the teeth extend outwardly on bothsides, as shown in Figure 3. To hold the teeth in the slots, teethretaining means are provided. In the modification of Figures 3, 4, 5 and6, the blades l2, l3 and I4 are notched, as at 22, preferably withrectangular notches, and the notches register with one another when theblades are assembled into a tooth. When the series of teeth is insertedin a disc I8, rings 24 of substantially rectangular cross-section areinserted in the notches and prevent the withdrawal or displacement ofany one tooth or any one blade l2, [3 or 14. The thickness of each ringis preferably the same as the depth of the notch or slot 22 in the toothand the ring fits snugly therein.

In those situations where a wider cutting or abrading surface isrequired than may conveniently be provided by a single tooth, aplurality of rows of teeth may be provided. The teeth in the severalrows are preferably staggered, respectively, as shown in Figure 1, andoverlap one another so that the entire area of the surface to be actedupon is treated by the teeth as the wheel revolves and no ridge ofuntreated material is left between the treated surfaces. Each tooth ofthe next adjacent series is slightly behind the tooth next ahead of itin order to permit the overlapping of adjacent teeth, that is, it is ina different radial plane through the axis.

As seen in Figures 1, 2 and 3, the several series of teeth are numberedH1, Hi), 2) and 3"], respectively. It is for the purpose of permittingthe blades to overlap, as shown, that the slotted discs [8 are madenarrower than the blades by the Widths of the two retaining or lookingrings 24. The rings 24 serve as spacers to separate the adjacent discsand permit adjacent teeth to overlap by being disposed one in a radialplane between the other. The discs 20, I20, 220, 320, etc. are assembledon an arbor 26 and clamped between end plates or end discs 28, Figure 3,the discs being all suitably apertured to receive the arbor. Theassembly is held on the arbor in any convenient manner as against a backup collar 30 by a nut 32 and washer 34.

Obviously only one series of teeth l0 may be used where a narrow cuttingmember is required, in which case one disc 20 suitably provided withteeth I0, is clamped between end plates 28. The

disc or discs and end plates comprise the hub' member of the tool.

It may be desirable, in some situations, that the front lamination, i.e., that lamination having the abrading edge, be of a different and/orhigher grade or heavier material than the socalled backing uplaminations.

In Figures 7 and 8, a modified tooth is illustrated. As before, thetooth comprises a plurality of blades 36, 38, 40, 42, 44 and 46, eachone slightly shorter than the tooth immediately in front of it(considering the direction of rotation as shown by the arrow). The discor hub 48 is formed, as before, with a plurality of radial slots, one ofwhich is shown at 50, and, in the lowermost part, the slot is widened asa rectangular passage 52 with downwardly and outwardly slop-v ing walls53. The lower end of, preferably, an equal number of the blades on eachside is bent away from the other group, as at 54, parallel to the wall53 of the slot and the bent ends 55 are locked against displacement,that is, wedged fast by a transverse rectangular pin or slug 56. Hereagain, the cutting blade 36 is backed by a Series of shorter blades eachone slightly longer than the blade immediately therebehind so that theblade will have flexibility and tend to bend on an are when in contactwith the work. By virtue of the Width of the slot 50, as viewed inFigure 7, greater flexibility of the tooth is aifo-rded since a greaternumber of backing up spring members 38, 40 etc. can be used, as shown,for a given length of tooth. Obviously, any means of securing the teethin the hub may be availed of.

In the modification of Figures 9, and 11, a tool with a single series ofteeth is shown. Such a tool is adapted particularly for small moldedarticles of relatively soft material or where a corner is to be cleaned.

A circular disc 69 is formed, at its periphery, with a plurality ofradial slots 62 to receive the teeth 64, 65 and 66 of this invention.The disc is of substantially constant thickness throughout and is formedcentrally with an aperture 68 of convenient size to receive, say, thearbor of a motor.

On either side of the disc 60 is an end plate 10. The two end plates areidentical in construction, merely facing in opposite directions. Theyare of substantially the same diameter as the disc 60 and are utilizedto retain the teeth in position. They, too, are formed with centralapertures 12 of the same diameter as that of the disc 6|].

In the illustrated embodiment, the end plates '36 are formed ascastings, interchangeable one with another. They are convenientlyreduced in thickness, as at 14, between a hub portion 15 and an annularthickened bearing portion 16 proximate the tooth engaging periphery, thehub '15 and spacing portion 16 contact to properly position the plateand disc and form a rigid construction with the slotted disc.Conveniently, at this shoulder portion 16 of increased thickness, thedisc and end plates are secured together, as by the rivets 78 or otherfastening means, the heads of which are preferably disposed, partiallyat least, in depressions formed in the outer faces of the plates orotherwise countersunk.

Outwardly of the shoulder 76, the inner or opposing faces of the endplates are recessed inwardly of the periphery, for a radial distancesomewhat greater than the depth of the radial grooves 62 in the disc toreceive the teeth. Each recess is formed with, or otherwise providedwith, an inwardly directed rib 80 preferably formed with bevelled sidewalls 82 to receive similarly shaped notches 6| of the teeth.

Thus, in assembly, the teeth 64-66 each comprised of a plurality oflaminations 64, 65, 66, in creasing in radial length, are inserted inthe peripheral grooves 62. These teeth, being of greater width than thesupporting disc Bl], extend outwardly on either side of the disc so thatthe notches 6| are substantially wholly exposed on the sides thereof.The notches 6| are preferably narrower at their bottom than at the mouthso that the sides 69 are sloping. The two end plates 10 are next appliedto the sides of the disc, the circular ribs 80 fitting into the notchesin the teeth and the walls of the recesses engaging the sides of theteeth. The tapering surface of the ribs 80 engage the tapering wall 69of the notches for rigidly securing the blades thereto. Then, when theend plates 10 are clamped against the disc by the rivets 18, the teethare firmly held in position by the ribs, in the notches of the teeth 64,65, 66.

The teeth are held against lateral displacement by the end plates. Theycannot be removed from the slots because of the ribs 80 and the radialwalls of the slots hold the teeth in a radial direction.

If desired, the several plates or leaves forming a tooth may bepermanently secured together as a unit, as by spotwelding at, forinstance, the point 84, Figure 10.

The tool of this invention replaces all of the existing abrading andpolishing brushes, wheels, etc. now on the market. It cuts and removesrust and scale on metal. It will also abrade hard and soft metals,moulded material and wood. It polishes the material where it has abradedit in one and the same operation. It will remove paint from wood andsmooth the roughened surface of cement more efiiciently and quicker thanwire brushes and has a life many times greater than wire brushes used inthis situation.

The resilient backing of the cutting tooth per:

mits each tooth to bend in an are instead of on a line at the point ofits security in the retaining hub and, therefore, there is no tendencyfor the tooth to break.

Due to the open spaces between the blades the temperature of the tool iskept very much lower than the temperature of the metal being acted upon.Moreover, where soft materials, such as wood, copper, aluminum andmoulded synthetic resinoids are acted upon, the material removed doesnot clog the teeth but probably due to the resiliency thereof, thematerial is thrown clear of the tool.

It will thus be seen that a cutting tool is provided which isself-cleaning and self-cooling and that the cutting or abrading elementsthereof do not clog and do not crystallize due to the supporting leaveswhich hold the cutting, i. e., the longest blades, toa curved flexureinstead of to a hinged flexure. With a relatively small number of discdiameters complete units of any desired diameter can be secured whilethe length of the tool can be readily varied by adding or subtractingunits in the assembly.

Various modifications will occur to those skilled in the art in theconfiguration, composition and disposition of the component elementsretaining the teeth in position as well as in the number and dispositionof such teeth and no limitation is intended by the phraseology of theforegoing specification or illustrations in the accompanying drawings.

What is claimed is:

In a rotary abrasive tool, a hub member and a plurality of flexiblelaminated teeth carried radially with the hub member, the respectivelaminations of each tooth lying in radial planes and increasingsuccessively in radial length in the direction of rotation of the hubmember, the inner ends of said laminations lying in the same planewhereby the lamination on the side toward the direction of rotation isthe longer and serves as the abrading edge.

ALBERT A. HODGKINS.

